babelrc-rollup

3.0.0 verified Sat Apr 25 auth: no javascript maintenance

Builds a Babel configuration for rollup-plugin-babel by reading a .babelrc file. Current stable version is 3.0.0 (August 2016, no recent updates). It simplifies Rollup integration by automatically converting presets to Rollup-compatible versions (e.g., es2015 → es2015-rollup) and adding the external-helpers plugin. Unlike manual configuration, it reads .babelrc and handles preset option passing (array syntax) for Babel v6.13+. Key differentiator: removes manual setup for Rollup+Babel, but is largely superseded by Rollup's built-in Babel handling.

Common errors

error Error: Cannot find module 'babel-preset-es2015-rollup' ↓

cause findRollupPresets enabled but the corresponding -rollup preset is not installed.

fix

Install the -rollup preset: npm install --save-dev babel-preset-es2015-rollup, or disable findRollupPresets.

error Error: .babelrc file not found ↓

cause The default path '.babelrc' does not exist or is not readable.

fix

Ensure a .babelrc file exists at the project root, or pass a custom path option to babelrc().

error TypeError: babelrc is not a function ↓

cause Wrong import style or version incompatibility (require instead of import or ES module mismatch).

fix

Use the default import: import babelrc from 'babelrc-rollup';

Warnings

breaking v3.0.0: findRollupPresets default changed from true to false. If you relied on automatic -rollup preset resolution, you must explicitly set findRollupPresets: true. ↓

fix Add findRollupPresets: true to the options object passed to babelrc().

breaking v2.0.0: findRollupPresets scans all presets for a -rollup suffix, which may pick up unintended replacements. ↓

fix Explicitly set findRollupPresets to false if you want exact preset matching, or upgrade to v3.0.0+.

deprecated The package is effectively unmaintained since August 2016. Modern Rollup and Babel versions may not work correctly. ↓

fix Consider using @rollup/plugin-babel with manual babel config or @babel/preset-env's modules: false.

gotcha addModuleOptions defaults to true, which sets modules: false for all presets. This may conflict with presets that already define modules options. ↓

fix Explicitly set addModuleOptions: false if your presets handle modules themselves.

gotcha addExternalHelpersPlugin defaults to true, which adds the external-helpers plugin. If not used, helpers may be duplicated. ↓

fix Set addExternalHelpersPlugin: false only if you are sure you don't need it.

Install

npm install babelrc-rollup

yarn add babelrc-rollup

pnpm add babelrc-rollup

Imports

default
wrong
```
const babelrc = require('babelrc-rollup')
```
correct
```
import babelrc from 'babelrc-rollup'
```
Default export; CommonJS require works but ESM is idiomatic for Rollup configs.
babelrc()
wrong
```
babelrc({ path: './.babelrc' })
```
correct
```
babelrc({ path: '.babelrc', addModuleOptions: true })
```
Path is relative to process.cwd() by default; do not include './' prefix.
babelrc with findRollupPresets
wrong
```
babelrc({ findRollupPresets: true, addModuleOptions: true })
```
correct
```
babelrc({ findRollupPresets: true })
```
Older versions (pre-3.0.0) enabled this by default. v3+ requires explicit opt-in.

Quickstart

Shows how to import babelrc-rollup and pass its output to rollup-plugin-babel in a Rollup config.

// rollup.config.js
import babelrc from 'babelrc-rollup';
import babel from 'rollup-plugin-babel';

export default {
  input: 'src/main.js',
  output: {
    file: 'dist/bundle.js',
    format: 'esm'
  },
  plugins: [
    babel(babelrc())
  ]
};